Rare Earth Doped Transition Metal Automobile Exhaust Purification Catalyst And Its Performance

A new type of catalytic materials of purification of automobile exhaust has been studied. The catalysts were made from CuO, MnOx, CeC>2 or their complex oxides such as bimetallic oxide catalyst Cu-Ce-O(x) with Cu(NOs)2, Mn(NC>3)2 and Ce(NO3)3 as initial materials. The catalysts were synthesized by impregnation method with its properties characterized through XRD and BET techniques, and its performance was tested with CO-NO and NHs-NO as probe molecules.The factors affecting their catalytic activities, such as impregnation period, global metal content on y -A^Os, calculations temperature and the period of calculations et al. have been investigated. Its catalytic activity was tested in a fixed-bed reactor by exposing the sample to the atmosphere of simulating automobile exhaust. The variation of the gas determined by gas chromatography. The main work carried out in the research is as followings.Firstly, I set up the testing system for automobile exhaust purification.Secondly, a series of samples were prepared by impregnation method. I initially investigated the effect of different preparing process on the activities of the catalysts by comparing the activity of different samples. The results showed that, to Cu-Ce-O(x) sample, 2h of the impregnation period, and the calcinations temperature was 700 癈, atom percent Cu/(Cu+Ce) =15 was controlled, the conversion of CO to COi by NO on the catalyst reached the maximum. As for Cu-Mn-Ce-O(x)/ Y -A^Os sample, when Cu:Mn;Ce=9:8:3 was controlled, calculations temperature was 500 癈 , the conversion of CO oxidation by NO was over 85% under the condition of 80癈 of reaction tempereture. Morever, the influence of CeO2 addition was also studied.Thirdly, the ability of the catalysts of resisting to SO2-poisoning was studied by exposing the Mn-Ce-O(x) and Cu-Mn-Ce-O(x) to the 160mL/min S02/air respectively for 16h at 500℃, then their activities for conversion of CO oxidation by NO .The conversion of NO reduction over the sulfated catalyst is somewhat higher than that over the fresh catalyst except that the optimum temperature increased about 100癈. Also at the optimum process for the experiment, the selective catalytic oxidation of CO by NO was 76% and the conversion of NO reduction was over 80% by NHj.What's more, we studied the effect of carriers on the activities. The samples were prepared on different carriers such as Y -A^Os, honeycomb cordierite and foam nic]4e respectively. Although they have similar activity, foam nickel wasn't a suitable carrier because it became breakable at high calculations temperature.